Permeability of PTFE studied with a potentiometric SO2-sensitive sensor

Permeability of PTEE to SO2 is studied by the least-squares fitting of the dynamic response of a potentiometric sensor with PTFE as gas-permeable memb rane. The proposed method establishes D x k product values for the diffusion of S O2 through PTFE that may be compared with the reported D x k product value at the diffusion through dimethylsilocone rubber. It also evidences morphol ogy differences between the considered PTFE samples, especially in the low concentration range that yield to the very long recovery time of the sensor , i.e. the variation of the superficial tension in the triphasic SO2/PTFE/i nternal electrolyte system. The method is accessible and may be used for the study of the permeability of other polymeric membranes or triphasic systems. (C) 2001 Elsevier Scienc e B.V. All rights reserved.